1981: Cearense Works located in state of Ceara; Araucaria works located in state of Parana.

1997: Gerdau acquisition of a holding in Acominas done together with NatSteel and the Acominas Employees' Association.

Ameristeel in 1999 was the second largest producer of rebar in the USA, with ownership of four minimills in Florida, Tennessee and North Carolina.

Gerdau Ameristeel Corporation was created through the 2003 merger of the North American steel operations of Gerdau and Canada's Co-Steel.

On its creation in 2003, Gerdau Acominas became responsible for the company's steelmaking in Brazil.

2005 acquisition by Gerdau of certain specialty steel assets in Spain was an important step for the company in getting entry into EU steel markets.

2007 Gerdau alliance in Dominican Republic was with Industrias Nacionales.

Sizuca Venezuela also known as Siderugica Zuliana. At the time of its acquisition by Gerdau, this was the 3rd largest steelmaker in Venezuela (a 300 kt/year long product mini mill).

2007 Quanex acquisition by Gerdau was for a consideration of ~$1.5 billion in cash, plus the assumption of debt and certain liabilities. MacSteel, the Quanex steel mill, was at the time of the Gerdau purchase the second largest producer of specialty steel long products in North America with annual production capacity of 1.2 million tonnes of steel and 1.1 million metric tonnes of rolled steel products. MacSteel has three steel mills based in Jackson (Michigan), Monroe (Michigan) and in Fort Smith (Arkansas), with 6 rolling mills in the states of Michigan, Ohio, Indiana and Wisconsin.

In 2007, Chaparral Steel operated two mini mills: one in Midlothian, Texas; the other in Dinwiddle County, Virginia.

New structural shapes facility in Mexico (through joint venture with Gerdau Corsa) will have annual installed capacity of ~1 million metric tonnes of steel and 700,000 tonnes of rolled products.

Cycle Systems, a metals recycling business acquired by Gerdau in 2013, has nine locations throughout central and western Virginia, including a shredder and several feed yards. Cycle Systems processed nearly 170,000 tonnes of materials in 2011.

2014: The plan is for Gerdau, together with the government of Minas Gerais, to expand its annual iron ore processing capacity to 24 million metric tonnes by 2020.

2015: Brazil's weak economy - hurt by a giant corruption scandal at state-run oil company Petrobras - saw tens of thousands of workers in Brazil lose their jobs since late 2014. Around 1700 workers are normally employed at Gerdau mill in Pindamonhangaba.

2016: In May 2016, police indicted more than a dozen people (including the company's chief executive officer Andrew Gerdau) for their alleged involvement in a tax evasion scandal.